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The Binalud Mountains: A key piece for the geodynamic puzzle of NE Iran
Author(s) -
Shabanian Esmaeil,
Bellier Olivier,
Siame Lionel,
Abbassi Mohammad R.,
Bourlès Didier,
Braucher Régis,
Farbod Yassaman
Publication year - 2012
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2012tc003183
Subject(s) - geology , seismology , alluvial fan , slip (aerodynamics) , fault (geology) , tectonics , quaternary , geodesy , geomorphology , paleontology , structural basin , physics , thermodynamics
We applied a combined approach of morphotectonic analyzes of SPOT‐5 satellite images and field surveys complemented by in situ‐produced 10 Be exposure dating to determine the kinematics and rate of active faulting in the Binalud Mountains bounded by the Neyshabur Fault System to the southwest and the Mashhad Fault Zone to the northeast. Three regional episodes of alluvial surface abandonment were dated at ∼4.8 ka (Q 1 ), ∼105 ka (Q 3 ), and ∼255 ka (S 3 ). Along the Neyshabur Fault System, cumulative offsets recorded by Q 3 fan surfaces yield slip rates of 2.4 ± 0.5 and 2.8 ± 0.6 mm/yr for right‐lateral and reverse components of active faulting (corresponding to an oblique slip rate of 3.6 ± 1.0 mm/yr), respectively. Reconstructing the cumulative right‐lateral offset recorded by S 3 surfaces, a maximum slip rate of 1.3 ± 0.1 mm/yr is suggested for the Mashhad Fault Zone. These imply an overall rate of 3.7 ± 0.6 mm/yr for the range‐parallel displacement and an uplift rate of ∼2.8 mm/yr due to the range‐normal shortening (1.6–2.2 mm/yr) during late Quaternary. The Binalud Mountains are deformed as a soft‐linked restraining relay zone, taking up the motion between central Iran and Eurasia at a rate of 4.0 ± 1.3 mm/yr; this translates central Iran in the ∼N340°E direction. Our data favor localized faulting, instead of distributed deformation, at the northeastern boundary of the Arabia‐Eurasia collision zone.